Green, Green, Green, Red

Green, Green, Green, Red is a colored pattern on Fringe. While most commonly shown in the form of colored circles, the pattern has also been shown in other forms, like flashing lights. They are a recurring motif on the show and could be seen throughout the series, including its final hours. With the exception of "The Equation," the Green, Green, Green, Red pattern (commonly refferred to as GGGR or the GGGR Pattern) is never specifically referenced in the show. It's common recurrence is simply an easter egg and does not have any particular significance.

The Green, Green, Green, Red pattern came to the attention of Fringe Division during their early Pattern investigations. Joanne Ostler used the combination of flashing Green, Green, Green, Red lights to put Jeremy Stockton into a hypnotic trance, allowing for her to kidnap his son, Ben. During further study, Walter determined that in this condition, people can respond to commands but have no knowledge of said actions or the passing of time. This continues until they are "awakened" with a simple touch. While in pursuit of Ben, Olivia was also a victim of the hypnotic effect of the colors. ("The Equation")

There are several instances of the Observers using this patten in their technology. It can be seen inside September's binoculars, on a device used to signal or control a hitman (not sure which), on the cap of a man who was chasing after the beacon in The Arrival, and in Donald's apartment in season 5. It is not clear why this pattern is so important to the Observers, or a least to the science team, but it is seen in many places involving them.